It was envisaged as a relaxing big game hunting mission for Sonny Bill Williams yet it was the former All Black who ultimately dodged a bullet as South Africa's "White Buffalo" insists he was robbed of certain victory after a controversial WBA International heavyweight title fight in Brisbane last night.

Williams' defeat of an aging though abrasive Francois Botha by unanimous decision inflicted yet another black eye on Australian sport during a week where the country's professional athletes already stand accused of involvement in rampant drug use and match-fixing.

Two international visitors then added to the ignominy as professional boxing produced yet another farcical footnote to a business already renowned for baffling adjudications.

Williams had been expected to put the 44-year-old self-proclaimed "Buffalo" out to pasture, extend his professional record to 6-0 and add the nondescript WBA belt to his list of sporting achievements before resuming his NRL career at the Sydney Roosters on Monday.

Instead a befuddled Williams' triumph was greeted by a crescendo of boos inside the Brisbane Entertainment Centre after the bout was sensationally trimmed from the originally scheduled 12 rounds to 10.

Botha plans to lodge a protest but regardless of the next step, Williams' first win over a credentialed opponent will forever be accompanied by an asterix.

Although Williams dominated the majority of an entertaining encounter, the ring-savvy Botha inflicted serious damage during the 10th and had essentially poleaxed the 27-year-old Kiwi before he was saved by the bell.

Williams was rocked by a series of blows in the dying stages and as he struggled to stay upright during a frantic final three minutes referee Tony Kettlewell deducted a point for holding.

The relief among the Williams camp was palpable when the fight ended with trainer Mick Akkawy leading the charge to support the jelly-legged superstar.

The judging panel's generous scoring of the bout 97-91, 98-94 97-91 in Williams' favour further incensed sectors of a crowd angered the contest had been trimmed by six minutes.

Botha geed up a boisterous 4000-strong throng by raising his arms in victory and during a brief ringside interview he labelled the outcome: "Bullshit".

Later in his dressing room Botha and trainer Hardy Mileham claimed they had been victims of a conspiracy to protect Williams' unbeaten record.

"At the press conference it was 12 rounds, in the programmes ... you cannot change it," Botha argued.

"If it had gone 12 rounds I would have killed him."

Mileham insisted the fight was set down for 12 three-minute rounds - a view supported by a graphic carried by the cable TV channel broadcasting the event.

The fact it had been shortened caught everyone off guard, particularly Botha and his corner.

Mileham said he was told during the eighth round the contest had been abbreviated, although he could not identify exactly who relayed the news.

Botha, meanwhile, said his game plan had been sabotaged by the alteration.

"I'm pacing myself and I always finish strong," said Botha.

"Championship rounds (fights) are 12 rounds.

"There I got screwed. He was out on his feet. All I had to do was push him away and he would have fallen.

"He held on and he got through it."

Although Williams was undoubtedly the finer physical specimen at the beginning of the main event, Botha used his 60 previous fights worth of experience to wear the novice down.

"I knew I'm going to break him down. This boy has never been later than six (rounds) so I'm going to get him.

"I was pacing myself to finish strong and 'boom' it didn't happen."

Botha sported a cut to the bridge of his nose and welts under both eyes though never sustained the type of cerebral punishment he inflicted on Williams.

But the pain of his ninth professional defeat still cut deep.

"How can you bend the rules because of a superstar in rugby?" he asked.

"He's a superstar, he should be winning .... everyone wants him to win, his management wants him to win but how can you go bend the rules? It's unheard of. They can't get away with it."

In tune with the puzzling end to the fight no WBA officials were available for comment - although Botha offered a solution.

"What the WBA should do now if they want to protect their name is immediately order a rematch and the real winner will arise."

Botha, who transformed himself from pantomime villain in the lead-up to the people's champion in the eyes of many, was gratified by the crowd reaction.

"I've got so much support here. People love me and that alone showed that I'm the winner," he said.

Williams also had his fair share of support in the stands and raised the prospect of a rematch in Cape Town although it is unlikely his manager Khoder Nasser would entertain another match-up with a fighter of Botha's durability.Nasser was inevitably in the spotlight during the confusing aftermath, claiming the fight was always going to span 10 rounds.

"My understanding was it was a 10 rounder. If it was a 12 rounder that's just a total misunderstanding.

"He won, and he won easily. Full stop. They can protest all they want," he stormed before deflecting attention to Botha's rough house tactics.

"From our side of the camp we felt there were a lot of things happening in the ring that were totally illegal.

"He got very desperate and very dirty."

Botha was deducted a point for persistently punching after the break in the ninth round, a dramatic stanza where he also succeeded in clocking Kettlewell twice.

But it was Williams who bore the brunt of Botha's fists and he was visibly subdued more than an hour after his torment ended.

Unwilling to put a timeframe on when he might factor in his seventh fight, an exhausted Williams said: "I'm just proud to have taken on someone with the experience he has and win out."